Ribbed structural board



1966 R. D. SCHULTHEISS 3,

RIBBED STRUCTURAL BOARD Original Filed May 4, 1959 INVENTOR. RALPH o.SCHULTHEISS #W ATTORNEY United States Patent 3,235,439 RllllBEDSTRUCTURAL BOARD Ralph D. Schultheiss, New Canaan, Conn., assignor tolnion Carbide Corporation, a corporation of New ork Original applicationMay 4, 1959, Ser. No. 810,793, now Patent No. 3,019,483, dated Feb. 6,1962. Divided and this application Sept. 7, 1961, Ser. No. 136,653

10 Claims. (Cl. 16169) The present invention relates to a plastic ribbedstructural board and, more particularly, to such a board which can beproduced in one extrusion operation without the need of additionalworking or fastening.

This is a division of my copending application entitled, Method andApparatus for Producing Extruded Structural Board, Serial No. 810,793,filed May 4, 1959, now Patent No. 3,019,483.

Heretofore, a great variety of plastic sheets and boards of variousshapes and sizes have been proposed which could be produced by one ormore extrusion steps combined with cutting and fastening steps. However,no ribbed structural board has been previously proposed which can beproduced in a single extrusion step with-out the need for additionalworking or fastening.

It is, therefore, the main object of the present invention to provide aplastic ribbed structural board which can be produced in a singleextrusion step without the need of additional working or fastening.

It is another object of the invention to provide an extruded plasticstructural board having interior ribs.

Other aims and advantages of the invention will become apparent from thefollowing description and appended claims.

In accordance with the present invention, there is provided a ribbedstructural board comprising at least two spaced apart, substantiallyparallel membranes of plastic and a multiplicity of plastic ribsdisposed between and attached to the membranes at right angles thereto.

The inventive board may be produced as an integral unit bysimultaneously extruding two sets of ribs on either side of an extrudedcentral membrane while outside membranes are simultaneously extruded andattached to the outer edges of the supporting ribs. Alternatively, thecentral membrane can be omitted. The ribs can be extruded in oscillatingor undulating paths on one or both sides of the central membrane, andthe rib paths on one side of the membrane need not be coincident withrib paths on the other side of the membrane.

The inventive structural board and a preferred method for producing thesame will now be described in greater detail by referring to thedrawings, in which:

FIG. 1 is an isometric view of the extrusion dies of the invention;

FIG. 2 is a cross-sectional View along the line 22 of FIG. 1;

FIG. 3 is a plan view of a portion of the surface of a typical extrudedstructural board; and

FIG. 4 is an isometric view of a modification of the apparatus of FIG.1.

FIG. 5 is an isometric view of a structural board of the inventionsimilar to that shown in plan View in FIG. 3.

Referring to FIGS. 1, 2, 3, and 5, a central plastic membrane 8 isextruded through the slot 9, formed by open slots in dies 14 and 16,slidably mounted in extrusion block 17 while ribs 10 and 12 aresimultaneously extruded through slots 11 and 13 respectively, adjacentto and leading out of slot 9. Slots 11 and 13 are disposed in slidableextruding dies 14 and 16 and the space between these dies forms slot 9.As plastic is extruded downward 3,235,439 Patented Feb. 15, 1966 throughslots 9, 1 1, and 13, dies 14 and 16 are reciprocated in oppositedirections so that ribs 10 and 12 from dies 14 and 16, respectively,follow oscillating paths on the central membrane and form thereby theinterior supports of the structural board.

Outside membranes 18 and 20 are extruded from slots 22 and 24,respectively, and these membranes join ribs 10 and 12 and are attachedthereto as shown in FIGS. 3 and 5. Membranes 18 and 20 form the outsidesurfaces of the structural board and can be composed of plastics ofvarious colors. Designs can be stamped or extruded thereon. To morefirmly bond membranes 18 and 20 to the ribs, means may be disposed belowthe die support to press the extruded membranes against the extrudedribs. For example, in FIG. 2 rollers 42 and 43 are disposed so as topress membranes 18 and 20 against the ribs 10 and 12. The rollers 41 and43 are rotatably mounted on rigid supporting members and 47,respectively. The temperature of the plastic should be not more thanabout C. less than the temperature of extrusion at the time the outsidemembranes are attached.

It is seen that varying the speed and regularity of the reciprocation ofextrusion dies 14 and 16 permits the supporting ribs to be placed in agreat many different designs. The structural board produced is strongand light and readily lends itself to a great number of uses forbuildings, advertising displays, furniture, etc.

In FIG. 4 is shown another embodiment of my inven tion. A support member26 having outside membrane extrusion slots 28 and 30 therein supportsslidably mounted extrusion dies 32 and 34 having coinciding slots 36therein. Unlike the extrusion device of FIG. 1, the extruder of FIG. 4is Without a central extrusion slot 9 so that interior supporting ribsextruded from slots 36 are integral with each other rather than with acentral membrane. The advantage of this variation is, of course, asaving in the amount of material used.

Any extrudable plastic, thermoplastic or thermosetting, can be used inthis invention. The temperature of extrusion will vary with the plasticsused.

What is claimed is:

1. An extruded plastic ribbed structural board comprising at least twospaced apart, substantially parallel membranes of plastic material, afirst layer of spaced plastic ribs integrally bonded to the innersurface of one of said membranes, and a second layer of spaced plasticribs integrally bonded to the inner surface of the other of saidmembranes, the ribs of said first layer continuously extending andforming integral intersections with the ribs of said second layerperiodically for the length of the board.

2. An extruded plastic ribbed structural board comprising, at least twospaced substantially parallel membranes of plastic material and at leasttwo layers of spaced plastic ribs situated between said membranes andsubstantially parallel therewith, the ribs of adjacent layers beingdisposed in periodic contact with one another to form integralintersections therebetween, the ribs of the layer adjacent each of saidmembranes being integrally bonded with said membrane along the lengthsthereof and at substantially right angles thereto.

3. The ribbed structural board of claim 2 wherein the ribs of adjacentlayers cross forming integral intersections therebetween.

4. The ribbed structural board of claim 2 wherein a plurality of theribs are shaped in undulating wave patterns along the length thereof.

5. The ribbed structural board of claim 2 wherein said ribs are shapedin undulating wave patterns along the lengths thereof and adjacent ribsin succeeding layers are positioned out of phase with one another.

6. The ribbed structural board of claim 2 having another membranedisposed between an adjacent pair of rib layers and integral therewith.

7. The ribbed structural board of claim 6 wherein said other membrane isdisposed between adjacent layers of crossing ribs and is integraltherewith.

8. The ribbed structural board of claim 6 having three spaced membraneswith one of said rib layers disposed between each pair of said membranesand integrally bonded thereto.

9. The ribbed structural board of claim 6 wherein the ribs of saidlayers are shaped in undulating wave patterns along the length thereof.

10. The ribbed structural board of claim 6 wherein said ribs are shapedin undulating wave patterns along the lengths thereof and adjacent ribsin succeeding layers are positioned out of phase with one another.

References Cited by the Examiner UNITED STATES PATENTS 1/1907 Gray161-123 12/ 1925 Tupper. 5/ 1927 Weiss. 2/ 1938 Budd.

7/1948 Gonda 154-459 3/1950 Kunz 181-331 12/1950 Lewis 161l23 7/ 1953Havens 161-68 1/ 1955 Daughterty. 1/ 1959 Goldstein.

FOREIGN PATENTS 12/ 1948 Italy.

1/ 1940 Netherlands.

EARL M. BERGERT, Primary Examiner.

1. AN EXTRUDED PLASTIC RIBBED STRUCTURAL BOARD COMPRISING AT LEAST TWOSPACED APART, SUBSTANTIALLY PARALLEL MEMBRANES OF PLASTIC MATERIAL, AFIRST LAYR OF SPACED PLASTIC RIBS INTEGRALLY BONDED TO THE INNER SURFACEOF ONE OF SAID MEMBRANES, AND A SECOND LAYER OF SPACED PLASTIC RIBSINTEGRALLY BONDED TO THE INNR SURFACE OF THE OTHER OF SAID MEMBRANES,THE RIBS OF SAID FIRST LAYER CONTINUOUSLY EXTENDING AND FORMING INTEGRALINTERSECTIONS WITH THE RIBS OF SAID SECOND LAYER PERIODICALLY FOR THELENGTH OF THE BOARD.